SJ-BG120A/200-01 (R) (Mitsubishi Electric)

SJ-BG120A/200-01 (R) is a Mitsubishi Electric SJ-BG series built-in AC spindle motor, designed for high-speed precision machining applications where the motor is integrated directly into the spindle assembly.

It belongs to Mitsubishi’s built-in spindle motor family, optimized for:

• compact spindle construction
• ultra-high rotational speed
• low vibration
• precision contour machining

The model is officially listed in Mitsubishi’s SJ-BG spindle specifications.

🔧 Model code breakdown

So:

SJ-BG120A/200-01(R) = 120 mm built-in spindle motor designed for ~20,000 rpm precision machining

🔧 Verified specifications

From Mitsubishi official SJ-BG spindle motor manuals:

⚙️ What makes the BG series special

Unlike conventional external spindle motors:

BG motors provide:

• ⚡ higher spindle RPM
• 🎯 better machining precision
• 📉 lower vibration
• 🧱 more compact spindle design
• 🔇 quieter operation

Official Mitsubishi spindle lineup documentation confirms SJ-BG as the built-in spindle family.

⚙️ What “(R)” means

The (R) suffix is used by Mitsubishi for:

• revised rotor configuration
• alternate balancing specification
• OEM/machine-builder customization

It is not a different motor family, but a variant of the same spindle platform.

🏭 Typical applications

SJ-BG120A/200-01(R) is commonly used in:

• high-speed machining centers
• mold & die machining
• graphite machining
• compact precision milling spindles
• fine finishing operations

It is selected when machines need:

• ⚡ high spindle speed (~20k rpm)
• 🎯 precision contour accuracy
• 📉 low vibration
• 🧱 compact integrated spindle construction

🧠 Simple explanation

SJ-BG120A/200-01(R) is a compact built-in CNC spindle motor designed for precision high-speed machining up to about 20,000 rpm, optimized for low vibration and compact spindle integration.